Which among the following is not a type of evidence?

In the context of evidence types relevant to legal and surveying practices, expert testimony is fundamentally distinct from the other options listed because it does not constitute a tangible form of evidence. Instead, expert testimony involves the opinions and insights of a qualified individual based on their expertise, often utilized to clarify complex issues or provide professional interpretation of data or findings.

Written evidence, parol evidence, and real evidence all represent forms of evidence that can be objectively examined or cross-verified. Written evidence includes documents, deeds, or contracts; parol evidence refers to verbal explanations or agreements that clarify the context of written documents; and real evidence encompasses physical objects or materials that can be seen or inspected.

Thus, while expert testimony plays a significant role in court and helps interpret various forms of evidence, it does not fall into the category of evidence types defined by physical or documented presence.